Sleep disturbances in Parkinson's disease

Sleep disturbance is one of the major sources of dissatisfaction with the q uality of life among patients with Parkinson's disease (PD). Nowadays it is clear that parkinsonian symptoms, tremor and rigidity, are alleviated duri ng sleep. The prevalence of sleep disturbances is difficult to ascertain; r eports vary from 98% to 74% to 81% to 73%, including patients suffering fro m excessive daytime sleepiness. Gender does not seem to play a clear role, although females may be more affected. Difficult sleep maintenance (light a nd fragmented sleep) and difficulties with sleep initiation are the earlies t and most frequent sleep disorders observed in PD. Other common sleep-asso ciated complaints include parasomnias and excessive daytime sleepiness (EDS )-that is, inappropriate and undesirable sleepiness during waking hours. Su rveys of the general population have shown that between 0.5% and 5% complai ned of EDS; even in a large study in an elderly population, about 20% of th e subjects reported 'usually sleepy in the daytime'. EDS is more common in PD. PD itself is one of the causes of sleep disturbance. Alteration of slee p-wake regulation may result from the disease process involving neuronal lo ss of locus coeruleus, substantia nigra, retrorubral nucleus, and pedunculo pontine nucleus. The severity of parkinsonian symptoms influences the degre e of sleep disturbance. Other common sleep-related motor complaints, includ ing nocturnal akinesia, dystonia, and painful cramps, are observed in parki nsonian patients who developed motor fluctuations (on-off phenomenon, weari ng off) during the day Depression is another common cause of sleep disturba nce. Other common disturbances are nocturia, fragmentary nocturnal myoclonu s, periodic leg movements of sleep, restless legs syndrome (RLS), and noctu rnal akathisia. In this paper, the preliminary results of our survey on sle ep disturbances in PD patients are also reported.